The objective of the proposed research is to evaluate possible mechanisms of autoantibody formation in rheumatoid arthritis and systemic lupus erythematosus. More specifically, the possible role of suppressor and helper T lymphocyte functions in autoantibody formation will be examined. Immunoglobulin (Ig) formation will be examined by a radioactive immunoassay technique and by a plague assay technique using sheep red blood cells coated with anti-immunoglobulin. The possible role of lysosomal proteases in rheumatoid synovial effusions in activating B cells to synthesize Ig and rheumatoid factor will also be examined. In addition, the effects of aggregated IgG on the synthesis of Ig by circulating peripheral blood leukocytes will continue to undergo study. Attempts will be made also to measure rheumatoid factor synthesis using sheep red blood cells coated with the fragments of IgG. Factors influencing Ig and rheumatoid factor synthesis will be investigated, partcularly the effects of helper and suppressor T cells. Similar experiments will be carried out using spleen cell suspensions from NZB/NZW F1 hybrid mice. It is hoped in this way to elucidate the mechanisms whereby increased Ig and rheumatoid factor synthesis occur in rheumatoid arthritis and systemic lupus erythematosus. BIBLIOGRAPHIC REFERENCES: Yamasaki, K., and Ziff, M., Enhancement of in vitro gamma globulin synthesis of rheumatoid lymphocytes by aggregated human gamma globulin (abstract), Arthr. Rheumat. 18:433, 1975. Jasin, H., and Aiff, M., Immunoglobulin synthesis by peripheral blood cells in systemic lupus erythematosus, Arthr. Rheumat. 18: 219-228, 1975.